Underwater buoy release systems responsive to acoustic signals are known in the prior art as exemplified by U.S. Pat. Nos. 5,022,013 to W. Dalton, et al., Jun. 4, 1991 and 5,184,328 to A. Dumestre, III, Feb. 2, 1993.
The latter patent discloses a system employing a thermally responsive actuator for both releasing and reattaching a tether line attaching a buoyed acoustic system to an object anchored underwater. Thus, upon receipt of a coded acoustic signal, a battery is connected to melt a wax body which expands to force an actuator member over a stroke which serves to detach the buoy from the tether line. There are significant advantages to use of the thermally responsive actuator for release from the tether line, however, this prior art system has the disadvantage of heavy battery drain whenever the buoy is reset for reuse which requires remelting the wax body.
Furthermore the line in prior art acoustic release systems does not always respond to the acoustic signal to permit the buoy to rise to the water surface because it may be tethered to the acoustic system in such a manner that the line may become fouled by action of underwater currents and waves.
It is therefore an object of the present invention to provide an improved thermally responsive acoustic release system that resolves these prior art problems.